The present invention relates to a method for controlling a clipping machine for producing sausage-shaped products according to claim 1 as well as a clipping machine for producing sausage-shaped products according to claim 8.
In particular, the present invention relates, besides the method for controlling a clipping machine, to a clipping machine for producing sausage-shaped products containing a flowable filling material, like a sealing compound, in a tubular casing material. The clipping machine comprising a filling tube for feeding filling material into the tubular casing material stored on the filling tube and being closed at the front end by a closing clip, a clipping device for placing and closing at least one closing clip on the on the back end of the tubular casing material just filled, and a control unit for controlling the clipping machine.
In the practice, it is known that, for example in the production of sausage-shaped products, filling material is fed by a filling machine through a filling tube of a clipping machine into a tubular casing material, which is stored on the filling tube and which is closed at its front end by a closing clip. The tubular casing material is pulled off from the filling tube while being filled. After a predetermined volume of filling material is filled into said tubular casing material, a displacement device with a first and a second pair of displacement elements forms a plait-like portion of the tubular casing material and the clipping machine places and closes at least one closing clip at the plait-like portion forming the back end of the sausage shaped product by respective closing tools which are reversibly movable towards the plait-like portion. After that, the sausage-shaped product just produced, is separated from the remaining casing material by a knife or the like of a cutting device of the clipping machine. The produced sausage-shaped product products may contain various flowable filling materials, e.g. sausage meat, grease, adhesives, sealing compounds or the like.
A clipping machine of this known type for producing sausages is disclosed in German patent application 198 24 829. In order to produce sausages of constant length and equal filling degree, the filling material is fed at a constant volumetric flow rate and the filling degree is sensed by a sensor acting on the just filled portion of the sausage to be produced. A casing break device is positioned in the region of the front end of the filling tube for applying a frictional force to the casing material while being pulled off from the filling tube. The sensor detects a deviation of the filling degree and activates the casing break device to readjust the pull-off speed of the tubular casing material. Furthermore, a counting wheel measures the pulled off length of the tubular casing material and stops the pulling-off when a predetermined length of the sausage is achieved. This device shall reduce casing material bursts by controlling the constant filling degree.
The pull-off speed of the casing material will be adapted to a varying filling degree. Thus, in case of a burst of the tubular casing material causing a deviation of the filling degree, at first the pull-off speed of the tubular casing will be re-adjusted. While trying to readjust said pull-off speed a large amount of filling material may escape from said burst casing material before the clipping machine will be stopped. Moreover, in case of a small material defect, like a leak, the known clipping machine will try to readjust the pull-off speed of the casing material for a much longer time, thereby the clipping machine will contaminated by the filling material escaping from said leak. Thus, even if said clipping machine would detect a burst of the tubular casing material or a leak in said casing material, it takes a long time from the occurrence of a burst or a leak to a respective reaction of the clipping machine, like a stop. In this time, a large amount of filling material contaminates the clipping machine and leads to time-consuming cleaning of the clipping machine, additional scrap-rates and production losses.